Receptor selective cannabimimetic aminoalkylindoles

ABSTRACT

Disclosed are cannabimimetic aminoalkylindole compounds and methos for their manufacture. The disclosed compounds are surprisingly potent and selective cannabinoinds. Also disclosed are methods of using the disclosed compounds, including use of the disclosed compounds to stimulate a cannabinoid receptor, to provide a physiological effect in an animal or individual and to treat a condition in an animal or individual.

This application is the National Stage of International Application No.PCT/US502/02501, filed Jan. 29, 2002, which claims the benefit of U.S.Provisional Application No. 60/264,855, filed Jan. 29, 2001, thecontents of each of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates generally to indole compounds exhibitingcannabimimetic activity. The present invention is more particularlyconcerned with new and improved aminoalkylindole compounds exhibitinghigh binding affinity for at least one cannabinoid receptor and/or highselectivity for one cannabinoid receptor, pharmaceutical preparationsemploying these compounds and methods of administering therapeuticallyeffective amounts of these compounds to provide a physiological effect.

BACKGROUND OF THE INVENTION

Classical cannabinoids such as the marijuana derived cannabinoidΔ⁹-tetrahydrocannabinol, (Δ⁹-THC) produce their pharmacological effectsthrough interaction with specific cannabinoid receptors in the body. Sofar, two cannabinoid receptors have been characterized: CB1, a centralreceptor found in the mammalian brain and peripheral tissues and CB2, aperipheral receptor found only in the peripheral tissues. Compounds thatare agonists or antagonists for one or both of these receptors have beenshown to provide a variety of pharmacological effects.

There is considerable interest in developing cannabimimetic compoundspossessing high affinity for one of the CB1 or CB2 receptors. Suchcompounds may offer a rational therapeutic approach to a variety ofdisease conditions. One class of cannabimimetic compound encompassesindole derivatives such as the well-known aminoalkylindoles representedby WIN 55212-2{(R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]-pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl](1-napthalenyl)methanone}.Aminoalkylindoles of this type typically have a carbon linkedalkylheterocyclic substituent at the indole-1 position, which isbelieved to be important for their cannabimimetic activities. Theseknown materials are not selective for preferential activation of one ofthe CB1 or CB2 receptors.

SUMMARY OF THE INVENTION

It has now been found that certain aminoalkylindoles possess surprisingcannabimimetic properties, including selectivity for the CB1 or CB2cannabinoid receptor. Broadly, in one aspect of the invention the novelcannabimimetic compounds can be represented by the structural formula Ibelow, physiologically acceptable salts, diasteromers, enantiomers,double bond isomers or mixtures thereof.

wherein:

Z comprises at least one substituent independently chosen from hydrogen;halogen; hydroxy; alkoxy; thioalkoxy; aryl and lower alkyl;

Alk comprises an alkyl group or a substituted alkyl group;

X comprises a 5, 6 or 7 member heterocyclic ring, including at least oneheteroatom independently selected from oxygen, nitrogen and sulfur; asubstituted 5, 6 or 7 member heterocyclic ring, including at least oneheteroatom independently selected from oxygen, nitrogen and sulfur; abicyclic ring; or a bicyclic ring including at least one heteroatomindependently selected from oxygen, nitrogen and sulfur;

R comprises hydrogen, CN, CHO, an alkyl group or a substituted alkylgroup;

Y comprises carbonyl, CH═CH (cis or trans), CONH or C═NH; and

Ar comprises adamantyl; azoadamantyl; phenyl; napthyl; 9-anthracenyl;pyridinyl; quinolinyl; isoquinolinyl; quinazolinyl; an aliphaticbicyclic ring; an azabicyclic ring; a heterobicyclic ring; any of theabove with no more than two substituents each independently selectedfrom amino, halogen, hydroxy, nitro, nitroso, azido, isothiocyanato,cyano, COOH, CONR³R⁴ where R³ and R⁴ each independently comprise H,alkyl or substituted alkyl, NCOR³R⁴ where R³ and R⁴ each independentlycomprise H, alkyl, substituted alkyl, CF₃, SO₂NR³R⁴ where R³ and R⁴ eachindependently comprise H, alkyl, substituted alkyl or CF₃; or a salt ofany of the above.

In one preferred aspect of the invention the novel compounds can berepresented by structural formula I above, wherein:

wherein:

Z comprises hydrogen;

Alk comprises a C₁₋₂alkyl group;

X comprises a 5, 6 or 7 member heterocyclic ring, including at least oneheteroatom independently selected from oxygen, nitrogen and sulfur; asubstituted 5, 6 or 7 member heterocyclic ring, including at least oneheteroatom independently selected from oxygen, nitrogen and sulfur; abicyclic ring; or a bicyclic ring including at least one heteroatomindependently selected from oxygen, nitrogen and sulfur;

R comprises hydrogen;

Y comprises carbonyl; and

Ar comprises adamantyl; azoadamantyl; phenyl; napthyl; 9-anthracenyl;

pyridinyl; quinolinyl; isoquinolinyl; quinazolinyl; an aliphaticbicyclic ring; an azabicyclic ring; any of the above with no more thantwo substituents each independently selected from amino, halogen,hydroxy, nitro, nitroso, azido, isothiocyanato, cyano, COOH, CONR³R⁴where R³ and R⁴ each independently comprise H, alkyl or substitutedalkyl, NCOR³R⁴ where R³ and R⁴ each independently comprise H, alkyl,substituted alkyl, CF₃, SO₂NR³R⁴ where R³ and R⁴ each independentlycomprise H, alkyl, substituted alkyl or CF₃; or a salt of any of theabove.

In another preferred aspect of the invention the novel compounds can berepresented by structural formula II below,

wherein:

Z comprises hydrogen;

R comprises hydrogen;

R¹ comprises N, O, S or CH₂;

R² comprises H, alkyl, CF₃, CH₂C═CH, CH₂CH═CH₂ or CH₂Ph; and

Ar comprises adamantyl; azoadamantyl; phenyl; napthyl; 9-anthracenyl;

pyridinyl; quinolinyl; isoquinolinyl; quinazolinyl; an aliphaticbicyclic ring; an azabicyclic ring; any of the above with no more thantwo substituents each independently selected from amino, halogen,hydroxy, nitro, nitroso, azido, isothiocyanato, cyano, COOH, CONR³R⁴where R³ and R⁴ each independently comprise H, alkyl or substitutedalkyl, NCOR³R⁴ where R³ and R⁴ each independently comprise H, alkyl,substituted alkyl, CF₃, SO₂NR³R⁴ where R³ and R⁴ each independentlycomprise H, alkyl, substituted alkyl or CF₃; or a salt of any of theabove.

Unless otherwise specifically defined, “alkyl” refers to a linear,branched or cyclic alkyl group having from 1 to about 9 carbon atomsincluding, for example, methyl, ethyl, propyl, butyl, hexyl, octyl,isopropyl, isobutyl, tert-butyl, cyclopropyl, cyclohexyl, cyclooctyl,vinyl and allyl. The alkyl group can be saturated or unsaturated andsubstituted or unsubstituted. Unless otherwise specifically defined,“lower-alcohol” refers to the general formula alkyl-OH. Unless otherwisespecifically defined, “alkoxy” refers to the general formula —O-alkyl.Unless otherwise specifically defined, “alkylmercapto” refers to thegeneral formula —S-alkl. Unless otherwise specifically defined,“alkylamino” refers to the general formula —(NH)-alkyl. Unless otherwisespecifically defined, “di-alkylamino” refers to the general formula—N-(alkyl)₂. Unless otherwise specifically defined, an aromatic ring isan unsaturated ring structure, substituted or unsubstituted, thatincludes only carbon as ring atoms. Unless otherwise specificallydefined, a heteroaromatic ring is an unsaturated ring structure,substituted or unsubstituted, that has carbon atoms and one or moreheteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms,for example, pyridine, furan, quinoline, and their derivatives. Unlessotherwise specifically defined, a carbocyclic ring is a saturated ringstructure, substituted or unsubstituted, that includes only carbon asring atoms, for example, cyclohexane. Unless otherwise specificallydefined, a heterocyclic ring is a saturated ring structure, substitutedor unsubstituted, that has carbon atoms and one or more heteroatoms,including oxygen, nitrogen and/or sulfur, as ring atoms, for example,piperidine, morpholine, piperazine, and their derivatives. Unlessotherwise specifically defined, an aliphatic bicyclic ring is apolycyclic structure, substituted or unsubstituted, having about 6 toabout 12 ring atoms that includes only carbon as ring atoms, for examplebicyclohexane and bicyclodecane. Unless otherwise specifically defined,a heterobicyclic ring is a polycyclic structure, substituted orunsubstituted, having about 6 to about 12 ring atoms that has carbonatoms and one or more heteroatoms, including oxygen, nitrogen and/orsulfur, as ring atoms, for example tropane.

Substituent groups useful in the invention are those groups that do notsignificantly diminish the biological activity of the inventivecompound. Unless otherwise specifically defined, substituent groups thatdo not significantly diminish the biological activity of the inventivecompound include, for example, alkyl, substituted alkyl, phenyl,substituted phenyl, OH, NH₂, alkoxy, halogen, CF₃, CN, NCS, azido,CONR³R⁴ where R³ and R⁴ each independently comprise H, alkyl orsubstituted alkyl, NCOR³R⁴ where R³ and R⁴ each independently compriseH, alkyl, substituted alkyl, CF₃, SO₂NR³R⁴ where R³ and R⁴ eachindependently comprise H, alkyl, substituted alkyl or CF₃, sulfonamide,or lower alcohol.

Some of the inventive cannabinoid compounds exhibit high affinity forthe CB1 and/or CB2 cannabinoid receptor. More specifically, some of theinventive analogs showed similar or higher receptor binding affinitythan the well-known indole cannabinoid WIN 5521 2-2. Thus, anotheraspect of the invention is use of at least one of the inventivecompounds to interact with a cannabinoid receptor.

Further, some of the inventive cannabinoid compounds show a surprisinglyhigher selectivity for one of the CB1 or CB2 cannabinoid receptors.These inventive selective compounds are able to interact with onecannabinoid receptor, for example the CB2 receptor, without affectingthe CB1 cannabinoid receptor to the same degree. More specifically, someof these compounds show not only comparable cannabimimetic activity withthe compound WIN 55212-2, but also a surprisingly higher selectivity forone of the CB1or CB2 receptors. Therefore, still another aspect of theinvention is use of at least one of the inventive compounds topreferentially interact with one cannabinoid receptor.

Some of the inventive cannabinoid compounds can act as high affinitymodulators for the CB2 cannabinoid receptor. The inventive cannabinoidcompounds therefore are potential therapeutic agents through themodulation of a cannabinoid receptor.

Some of the novel cannabinoid compounds described herein may be agonistsfor at least one of the cannabinoid receptors. The inventive cannabinoidagonists interact with the at least one cannabinoid receptor bindingsite to initiate a physiological or a pharmacological responsecharacteristic of that receptor. Therefore, a further aspect of theinvention is use of at least one of the inventive compounds to initiatean agonistic response from a cannabinoid receptor.

Some of the novel compounds described herein may be cannabinoid receptorantagonists. The inventive cannabinoid antagonists interact with the CB1and/or CB2 cannabinoid receptor binding site to block other ligands fromthe receptor binding site without initiating a physiological or apharmacological response characteristic of that receptor. Thus,cannabinoid antagonists typically oppose the cannabinoid receptor siteresponse characteristics initiated by cannabinoid agonists. Therefore, afurther aspect of the invention is use of at least one of the inventivecompounds to oppose initiation of an agonistic response from acannabinoid receptor.

The inventive cannabinoid compounds described herein, andphysiologically acceptable salts thereof, have pharmacologicalproperties when administered in therapeutically effective amounts forproviding a physiological response in individuals and/or animals. Thus,another aspect of the invention is the administration of atherapeutically effective amount of at least one of the inventivecannabimimetic compounds, or a physiologically acceptable salt thereof,to an individual or animal to provide a physiological response.

Additionally, some of the halogen containing analogs, for example thoseanalogs comprising iodide and fluoride, are potential radioactive probesfor imaging in vivo the distribution of cannabinoid receptors.

A better understanding of the invention will be obtained from thefollowing detailed description of the article and the desired features,properties, characteristics, and the relation of the elements as well asthe process steps, one with respect to each of the others, as set forthand exemplified in the description and illustrative embodiments.

DESCRIPTION OF A PREFERRED EMBODIMENT

As used herein, a “therapeutically effective amount” of a compound, isthe quantity of a compound which, when administered to an individual oranimal, results in a sufficiently high level of that compound in theindividual or animal to cause a discernible increase or decrease instimulation of cannabinoid receptors. Such discernible increase ordecrease in stimulation of cannabinoid receptors can provide aphysiological effect in the individual or animal.

Physiological effects that result from CB1 cannabinoid receptorinteraction with agonist compounds include relief of pain, peripheralpain, neuropathic pain, glaucoma, epilepsy and nausea such as associatedwith cancer chemotherapy; appetite enhancement; selective killing ofglioma and breast cancer cells; alleviation of the symptoms ofneurodegenerative diseases including Multiple Sclerosis, Parkinson'sDisease, Huntington's Chorea and Alzheimer's Disease, reduction offertility; prevention or reduction of diseases associated with motorfunction such as Tourette's syndrome; neuroprotection; suppression ofmemory and peripheral vasodilation. Physiological effects that resultfrom CB1 cannabinoid receptor interaction with antagonist compoundsinclude appetite suppression; memory enhancement; beneficial effects inmental disorders such as schizophrenia and depression; and beneficialeffects in endotoxic and hypotensive shock. Physiological effects thatresult from CB2 cannabinoid receptor interaction with agonist compoundsinclude relief of pain, peripheral pain, neuropathic pain, glaucoma,epilepsy and nausea such as associated with cancer chemotherapy;selective killing of glioma and breast cancer cells; alleviation of thesymptoms of neurodegenerative diseases including Multiple Sclerosis,Parkinson's Disease, Huntington's Chorea and Alzheimer's Disease,reduction of fertility; prevention or reduction of diseases associatedwith motor function such as Tourette's syndrome; prevention or reductionof inflammation; neuroprotection; and suppression of the immune system.Physiological effects that result from CB2 cannabinoid receptorinteraction with antagonist compounds include enhancement of the immunesystem and peripheral vasoconstriction. Typically a “therapeuticallyeffective amount” of the novel compounds ranges from about 10 mg/day toabout 1,000 mg/day.

As used herein, an “individual” refers to a human. An “animal” refersto, for example, veterinary animals, such as dogs, cats, horses and thelike, and farm animals, such as cows, pigs and the like.

The compound of the present invention can be administered by a varietyof known methods, including orally, rectally, or by parenteral routes(e.g., intramuscular, intravenous, subcutaneous, nasal or topical). Theform in which the compounds are administered will be determined by theroute of administration. Such forms include, but are not limited to,capsular and tablet formulations (for oral and rectal administration),liquid formulations (for oral, intravenous, intramuscular orsubcutaneous administration) and slow releasing microcarriers (forrectal, intramuscular or intravenous administration). The formulationscan also contain a physiologically acceptable vehicle and optionaladjuvants, flavorings, colorants and preservatives. Suitablephysiologically to acceptable vehicles may include, for example, saline,sterile water, Ringer's solution, and isotonic sodium chloridesolutions. The specific dosage level of compound will depend upon anumber of factors, including, for example, biological activity of theparticular preparation, age, body weight, sex and general health of theindividual being treated.

The following examples are given for purposes of illustration only inorder that the present invention may be more fully understood. Theseexamples are not intended to limit in any way the scope of the inventionunless otherwise specifically indicated.

The prepared cannabimimetic indole derivatives can generally bedescribed with reference to exemplary structural formulas 1 and 2 below.

The inventive compounds of exemplary structural formula 1 include bothracemics and two enantiomers and are listed in TABLE 1.

It should be noted that alk-X for all of the materials of TABLE 1 was 1-(N-methyl-2-piperidinyl)methyl.

TABLE 1 K_(i) nM analog Z R Ar CB1 CB2 2-7(R, S) H H2-iodo-5-nitrophenyl 403 5.7 2-7(R) H H 2-iodo-5-nitrophenyl 285 0.532-7(S) H H 2-iodo-5-nitrophenyl 906 9.5 2-7(R, S) H H2-iodo-5-nitrophenyl 1.6 human 2-24(R) H H 2-iodophenyl 1.8 2.1 2-24(S)H H 2-iodophenyl 561 583Surprisingly, and as exemplified by compounds 2-7 and 2-24, in all casesthe + configuration (R configuration) has a higher selectivity for theCB2 receptor and a higher affinity for the CB2 receptor.

Compound 2-7 was tested for binding affinity to human CB2 receptorsusing the below described procedure with human tissue samples. Thatcompound was found to be a surprisingly potent cannabinoid.

TABLE 2 Ki nM analog Z R R¹ R² Ar CB1 CB2 2-25 H H O CH₂Ph

1217 1800 2-26 H H O CH₂Ph

4212 1431 2-27 H H O CH₂Ph

2383 927.5 2-28 H H O CH₃

27.93 226.3 2-29 H H O CH₃

848.1 48.45 2-30 H H O CH₃

464.3 153.5 2-31 H H O CH₃

5.696 26.56 2-32(R,S) H H CH₂ CH₃

239.4(R,S) 3.411(R,S) 2-32(R) H H CH₂ CH₃

139.7(R) 1.416(R) 2-32(S) H H CH₂ CH₃

2029(S) 160.5(S) 2-32(R,S)human H H CH₂ CH₃

13.60(R,S),Human 2-32(R)human H H CH₂ CH₃

6.688(R),Human 2-33 H H CH₂ CH₃ 1-Adamantyl 11.93 4.804 2-33 H H CH₂ CH₃1-Adamantyl 2.321 human Human 2-34(R,S) H H CH₂ CH₃

2.889(R,S) 3.345(R,S) 2-34(R) H H CH₂ CH₃

1.573(R) 1.558(R) 2-34(S) H H CH₂ CH₃

14.17(S) 6.789(S) 2-34(R,S)human H H CH₂ CH₃

2.488Human 2-35 H H CH₂ CH₃

14.36 20.93 2-36 H H CH₂ CH₃

133.1 8.532 2-37 H H CH₂ CH₃

3541 836.6 2-38 H H CH₂ CH₃

719.3 747.5 2-39 H H CH₂ CH₃

41.44 19.53 2-40 H H CH₂ CH₃

28.65 14.54 2-41 H H CH₂ CH₃

157.8 159.7 2-42 H H CH₂ CH₃

421.4 147.2 2-43 H H CH₂ CH₃

8816 1858 2-44 H H CH₂ CH₃

16.94 7.037 2-45 H H CH₂ CH₃

418.5 15.82 2-46 H H CH₂ CH₃

338.7 15.41 2-47 H H CH₂ CH₃

240.2 18.76 2-48 H H CH₂ CH₃

390.0 47.17 2-49 H H CH₂ CH₃

29.07 18.63 2-50 H H CH₂ CH₃

2-51 H H CH₂ CH₃

2-52 H H CH₂ CH₃

2-53 H H CH₂ CH₃

Preparation of Compounds

The above materials were generally prepared following Scheme 1 with theexception that N-methyl-2-piperidinemethyl chloride is used in place ofacetoxylalkylhalides for the alkylation of the indole 1-position.

When Z═NO₂, the structures can be transformed to different substituentsusing methods outlined in Scheme 2.

The commercially unavailable R3-COCl used in Scheme 1 can be preparedaccording to Scheme 3.

After these acid chlorides are connected at the indole 3-position, thenitro group therein can be further transformed into amino, iodo, azido,and isothiocyanate groups according to the methods outlined in Scheme 4.

Examples of specific analogs were perpared as follows:

1-(N-Methyl-2-piperidinyl)methyl-3-(3-quinolinecarbonyl)-1H-indole

To the suspension of 200 mg (1.5 mmol) of anhydrous AlCl₃ in 8 mlabsolute methylene chloride was added 287.4 mg (1.5 mmol)3-quinolinecarbonyl chloride in 5 ml methylene chloride and the reactionmixture was stirred 30 min at room 22–25° C. The(N-Methyl-2-piperidinyl)methyl-1H-indole 228.3 mg (1.0 mmol) in 5 ml ofmethylene chloride was added by dropwise during 1.5 h and the mixturestirred 36 h. The reaction was work-up by addition of 20 ml 2M solutionof sodium hydroxide and extracted by ethyl acetate (3×20 ml). Thecombined extract dried by sodium sulfate. After removing of solvents therest (0.365 g) was purified by chromatography (silica gel,toluene-triethylamine, 10:1).

1-(N-Methyl-2-piperidinyl)methyl-3-(1-adamantanecarbonyl)-1H-indole

To the stirring solution of the diethyl aluminum chloride (1.5 ml 1 Msoln. in hexane, 180.8 mg, 1.5 mmol) in 10 ml absolute methylenechloride was added at room temp. 298.0 mg (1.5 mmol)1-adamantanecarbonyl chloride in 5 ml of methylene chloride and thereaction mixture was stirred 15 min. The solution of(N-Methyl-2-piperidinyl)methyl-1H-indole (228.3 mg, 1.0 mmol) in 5 ml ofmethylene chloride was added during 3 min and mixture was stirred andreflux 48 h. The reaction was work-up by addition of 20 ml 2M solutionof sodium hydroxide and extracted by ethyl acetate (3×20 ml), washed totimes by water and two times by brine. The combined extract dried by themixture of sodium sulfate and potassium carbonate. After removing ofsolvents the rest was purified by chromatography (silica gel, methanolethyl acetate 1:1).

1-(N-Methyl-2-piperidinyl)methyl-3-(2-iodo-5-cyano)benzoyl-1H-indole

1-(N-Methyl-2-piperidinyl)methyl-3-(2-iodo-5-amino)benzoyl-1H-indole(111.6 mg, 0.236 mmol) was dissolved in 3 ml of water containing 43 mg(1.179 mmol) of hydrogen chloride (101 mkl 38% HCl in 3 ml H₂O). Thethis solution was added at stirring sodium nitrite 16.64 mg (0.241 mmol)in 1 ml of water at 0° C. After 1 h the obtained diazonium salt wasgradually added to solution of cuprous cyanide (23.5 mg, 0.264 mmol) insodium cyanide (28.25 mg (0.528 mmol) in 1 ml of water at 60° C. Thereaction mixture was diluted by water, extracted ethyl acetate (3×15ml), dried sodium sulfate and after removing of solvent purified bychromatography (silica gel, methanol-ethyl acetate, 1:2).

A person of ordinary skill in the art, understanding the disclosures forthe general preparation and specific preparation examples would know howto modify the disclosed procedures to achieve the above listed analogs.

The prepared cannabinoid compounds were tested for CB2 receptor bindingaffinity and for CB1 receptor affinity (to determine selectivity for theCB2 receptor). As used herein, “binding affinity” is represented by theIC₅₀ value which is the concentration of an analog required to occupythe 50% of the total number (Bmax) of the receptors. The lower the IC₅₀value, the higher the binding affinity. As used herein a compound issaid to have “binding selectivity” if it has higher binding affinity forone receptor compared to the other receptor; e.g. a compound that has anIC₅₀ of 0.1 nM for CB1 and 10 nM for CB2 , is 100 times more selectivefor the CB1 receptor. The binding affinities (K_(i)) are expressed innanomoles (nM).

For the CB1 receptor-binding studies, membranes were prepared from ratforebrain membranes according to the procedure of P. R. Dodd et al; ARapid Method for Preparing Synaptosomes: Comparison with AlternativeProcedures, Brain Res., 107–118 (1981). The binding of the novelanalogues to the CB1 cannabinoid receptor was assessed as described inW. A. Devane et al; Determination and Characterization of a CannabinoidReceptor in a Rat Brain, Mol. Pharmacol., 34, 605–613 (1988) and A.Charalambous et al; “5′-azido ⁸⁻-THC: A Novel Photoaffinity Label forthe Cannabinoid Receptor”, J. Med. Chem., 35, 3076–3079 (1992) with thefollowing changes. The above articles are incorporated by referenceherein.

Membranes, previously frozen at −80° C., were thawed on ice. To thestirred suspension was added three volumes of TME (25 mM Tris-HClbuffer, 5 mM MgCl₂ and 1 mM EDTA) at a pH 7.4.The suspension wasincubated at 4° C. for 30 min. At the end of the incubation, themembranes were pelleted and washed three times with TME.

The treated membranes were subsequently used in the binding assaydescribed below. Approximately 30 μg of membranes were incubated insilanized 96-well microtiter plate with TME containing 0.1% essentiallyfatty acid-free bovine serum albumin (BSA), 0.8 nM [³H] CP-55,940, andvarious concentrations of test materials at 30° C. for 1 hour. Thesamples were immediately filtered using a Packard Filtermate 196 andWhatman GF/C filterplates and washed with wash buffer (TME) containing0.5% BSA. Radioactivity was detected using MicroScint 20 scintillationcocktail added directly to the dried filterplates, and the filterplateswere counted using a Packard Instruments Top-Count. Nonspecific bindingwas assessed using 100 nM CP-55,940. Data collected from threeindependent experiments performed with duplicate determinations wasnormalized between 100% and 0% specific binding for [³H] CP-55,940,determined using buffer and 100 nM CP-55,940.The normalized data wasanalyzed using a 4-parameter nonlinear logistic equation to yield IC₅₀values. Data from at least two independent experiments performed induplicate was used to calculate IC₅₀ values which were converted toK_(i) values using the using the assumptions of Cheng et al;“Relationship Between the Inhibition Constant (K_(i)) and theconcentration of Inhibitor which causes 50% Inhibition (IC₅₀) of anEnzymatic Reaction”, Biochem. Pharmacol., 22, 3099–3102, (1 973), whichis incorporated by reference herein.

For the CB2 receptor binding studies, membranes were prepared fromfrozen mouse spleen essentially according to the procedure of P. R. Doddet al; “A Rapid Method for Preparing Synaptosomes: Comparison withAlternative Procedures”, Brain Res., 226, 107–118 (1981) which isincorporated by reference herein. Silanized centrifuge tubes were usedthroughout to minimize receptor loss due to adsorption. The CB2 bindingassay was conducted in the same manner as the CB1 binding assay. Thebinding affinities (K_(i)) were also expressed in nanomoles (nM). Thestructures, binding affinities and selectivities are summarized in Table1.

As can be seen from the results in TABLES 1 and 2, some of thecompounds, for example, 2-7, show a high selectivity for the CB2receptor. The inventive compounds described herein have high potentialwhen administered in therapeutically effective amounts for providing aphysiological effect useful to treat a variety of disease conditions.Naturally, the invention also encompasses any physiologically acceptablesalts, diasteromers, enantiomers, double bond isomers and mixtures ofthe above inventive compounds.

In addition, some of the iodide and fluoride containing compounds, forexample, 2-7 or 2-24, are potential radioactive probes which would beuseful for imaging in vivo the distribution of cannabinoid receptors.Further, azido containing compounds would be useful as affinity probesfor characterizing binding pockets of cannabinoid receptors.

While preferred embodiments of the foregoing invention have been setforth for purposes of illustration, the foregoing description should notbe deemed a limitation of the invention herein. Accordingly, variousmodifications, adaptations and alternatives may occur to one skilled inthe art without departing from the spirit and scope of the presentinvention.

1. A compound of the formula below, or the physiologically acceptablesalts, diasteromers, enantiomers, double bond isomers, or mixturesthereof:

wherein: Z is hydrogen; R is hydrogen; R¹ is selected from NH, O, S orCH₂; R² is selected from CH₃, CF₃, CH₂C≡CH, CH₂CH₂═CH₂ or CH₂Ph; and Aris selected from; phenyl with no more than two substituents eachindependently selected from amino, halogen, hydroxy, nitro, nitroso,azido, isothiocyanato, cyano; COOH, CONR³R⁴ where R³ and R⁴ are eachindependently selected from H, alkyl or substituted alkyl, NCOR³R⁴ whereR^(b 3) and R⁴ are each independently selected from H, alkyl,substituted alkyl or CF₃ and NSO₂R³R⁴ where R³ and R⁴ are eachindependently selected from H, alkyl, substituted alkyl or CF₃; naphthylwith no more than two substituents each independently selected fromamino, halogen, hydroxy, nitro, nitroso, azido, isothiocyanato, cyano orCOOH, CONR³R⁴ where R³ and R⁴ are each independently selected from H,alkyl or substituted alkyl, NCOR³R⁴ where R³ and R⁴ are eachindependently selected from H, alkyl, substituted alkyl or CF₃, NSO₂R³R⁴where R³ and R⁴ are each independently selected from H, alkyl,substituted alkyl or CF₃; or a salt of any of the above, with theprovisos that: if R² is CH₃ or CH₂Ph; then Ar cannot be unsubstitutedphenyl; phenyl substituted by from one to two substituents selected fromthe group consisting of fluorine, chlorine, bromine, hydroxy, nitro andamino; 1- or 2-naphthyl or 1- or 2-naphthyl substituted by from one totwo substituents selected from the group consisting of fluorine,chlorine and bromine; and if R¹ is CH₂ and R² is CH₃; then Ar cannot bephenyl substituted by from one to two halogen atoms; 1- or 2-naphthyl or1- or 2-naphthyl substituted by from one to two substituents selectedfrom the group consisting of halogen, hydroxy, and cyano; anthracenyl oranthracenvl substituted by from one to two substituents selected fromthe group consisting of fluorine, chlorine, bromine hydroxy, and cyano.2. The compound of claim 1, wherein: Z is H; R is H; R¹ is CH₂; R² isCH₃; and Ar is 2-iodo-5-nitrophenyl.
 3. A pharmaceutical preparationcomprising a therapeutically effective amount of a compound of theformula below, or the physiologically acceptable salts, diasteromers,enantiomers, double bond isomers or mixtures thereof:

wherein: Z is hydrogen; Alk is selected from an alkyl group or asubstituted alkyl group; X is selected from 6 member heterocyclic ring,including at least one heteroatom independently selected from oxygen,nitrogen and sulfur; a substituted 6 member heterocyclic ring, includingat least one heteroatom independently selected from oxygen, nitrogen andsulfur; and the Alk moiety bonds to a ring carbon atom of the X moiety;R is selected from hydrogen, an alkyl group or a substituted alkylgroup; Y is carbonyl ; and Ar is selected from phenyl; naphthyl;9-anthracenyl; an aliphatic bicyclic ring; any of the above with no morethan two substituents each independently selected from amino, halogen,hydroxy, nitro, nitroso, azido, isothiocyanato, cyano, COOH, CONR³R⁴where R³ and R⁴ are each independently selected from H, alkyl orsubstituted alkyl, NCOR³R⁴ where R³ and R⁴ are each independentlyselected from H, alkyl, substituted alkyl or CF₃, NSO₂R³R⁴ where R³ andR⁴ are each independently selected from H, alkyl, substituted alkyl orCF₃; or a salt of any of the above; with the provisos that: if X is anunsubstituted 6 member heterocyclic ring or a 6 member heterocyclic ringsubstituted with at least one member selected from the group consistingof alkyl, hydroxy, benzyl or lower alkoxvbenzyl; and R is H or an alkylgroup; then Ar cannot be unsubstituted phenyl; phenyl substituted byfrom one to two substituents selected from the group consisting offluorine, chlorine, bromine, hydroxy, nitro and amino; 1- or 2-naphthylor 1- or 2-naphthyl substituted by from one to two substituents selectedfrom the group consisting of fluorine, chlorine and bromine; if X is anunsubstituted 6 member heterocyclic ring or an alkyl substituted 6member heterocyclic ring; and R is H or an alkyl group; then Ar cannotbe phenyl substituted by from one to two halogen atoms; 1- or 2-naphthylor 1- or 2-naphthyl substituted by from one to two substituents selectedfrom the group consisting of halogen, hydroxy and cyano; anthracenyl oranthracenyl substituted by from one to two substituents selected fromthe group consisting of halogen, hydroxy, and cyano; and if X is anunsubstituted 6 member heterocyclic ring including both nitrogen andoxygen as ring heteroatoms: and R is H or an alkyl group: then Ar cannotbe phenyl substituted by cyano; naphthyl substituted by a singlesubstituent selected from the group consisting of hydroxy, nitro, amino,and isothiocyano: or anthracenyl.
 4. The pharmaceutical preparation ofclaim 3 wherein: Z is H; Alk is CH₂; X is a 6 member heterocyclic ringcontaining a single hetero nitrogen atom; R is H; Y is carbonyl; and Aris iodo, nitrophenyl.
 5. The pharmaceutical preparation of claim 3wherein the compound is

including physiologically acceptable salts, diasteromers, enantiomers,double bond isomers, or mixtures thereof.
 6. The compound of claim 1 ofthe formula:


7. A compound of the formula, or the physiologically acceptable salts,diasteromers, enantiomers, double bond isomers, or mixtures thereof:

wherein: Z is hydrogen; R is hydrogen; R¹ is selected from NH, O, S orCH₂; R² is selected from CH₃, CF₃, CH₂C≡CH, CH₂CH═CH₂ or CH₂Ph; and Aris selected from an aliphatic bicyclic ring or an aliphatic bicyclicring with no more than two substituents each independently selected fromamino, halogen, hydroxy, nitro, nitroso, azido, isothiocyanato, cyano,COOH, CONR³R⁴ where R³ and R⁴ are each independently selected from H,alkyl or substituted alkyl, NCOR³R⁴ where R³ and R⁴ are eachindependently selected from H, alkyl, substituted alkyl, or CF₃, andNSO₂R³R⁴ where R³ and R⁴ are each independently selected from H, alkyl,substituted alkyl or CF₃; or a salt of any of the above, with theproviso that: if R is H or alkyl; and R¹ is CH₂; and R² is CH₃; then Arcannot be 1,2,3,4-tetrahydronaphthyl or 1,2,3,4-tetrahydronaphthylsubstituted by from one to two substituents selected from the groupconsisting of halogen, hydroxy and cyano.
 8. The compound of claim 1,wherein: Z is H; R is H; R¹ is CH₂; R² is CH₃; and Ar is phenylsubstituted with a single I atom and a single CN moiety.
 9. The compoundof claim 1, wherein: Z is H; R is H; R¹ is CH₂; R² is CH₃; and Ar is


10. The pharmaceutical preparation of claim 3, wherein: Alk is CH₂; X isa substituted 6 member heterocyclic ring including a single nitrogenatom; R is H; and Ar is phenyl substituted with a single I atom and asingle CN moiety.
 11. The pharmaceutical preparation of claim 3,wherein: Alk is CH₂; X is a substituted 6 member heterocyclic ringincluding a single nitrogen atom; R is H; and Ar is